579 results about "Intergranular corrosion" patented technology

A low Ni and high N austenitic-ferritic stainless steel is disclosed. It includes an austenitic-ferritic stainless steel having high formability and punch stretchability, crevice corrosion resistance, corrosion resistance at welded part, or excellent intergranular corrosion resistance, from a stainless steel structured by mainly austenite phase and ferrite phase, and consisting essentially of 0.2% or less C, 4% or less Si, 12% or less Mn, 0.1% or less P, 0.03% or less S, 15 to 35% Cr, 3% or less Ni, and 0.05 to 0.6% N, by mass, by adjusting the percentage of the austenite phase in a range from 10 to 85%, by volume. Furthermore, it includes an austenitic-ferritic stainless steel having higher formability by adjusting the amount of (C+N) in the austenite phase to a range from 0.16 to 2% by mass.

Recrystallized lead and lead alloy positive current collectors and connectors such as straps and lugs for use e.g. in lead acid batteries and electrowinning anodes, having an increased percentage of special grain boundaries in at least part of the microstructure, which have been provided by a process comprising of (i) cold or hot rolling or cold or hot extrusion or (ii) steps of deforming the lead or lead alloy, and subsequently annealing the lead or lead alloy. Either a single cycle of working and annealing can be provided, or a plurality of such cycles can be provided. The amount of deformation, the recrystallization time and temperature, and the number of repetitions of such steps are selected to ensure that a substantial increase in the population of special grain boundaries is provided in the microstructure, to improve resistance to creep, intergranular corrosion and intergranular cracking of the current collectors and connectors during battery service, and result in extended battery life and the opportunity to reduce the size and weight of the battery.

The invention relates to a process for welding duplex stainless steel, in particular to the process for welding the duplex stainless steel used for high-sulfur content refining equipment, highly-corrosive petrochemical equipment and pipelines, high-parameter power devices, and the chloridion-corroded environments of seawater and the like. In the process, a specific protective gas favorable for the welding of the duplex stainless steel is adopted, and simultaneously limited linear energy and inter-layer temperature are regulated in the welding process, so that the unfavorable defects of the conventional welding process can be overcome, and a metallographic structure with the ferrite content of 30 to 70 percent and a ferritic phase in percentage equivalent to that of an austenitic phase is obtained. A welding joint obtained by the welding process has high mechanical properties, high strength and hardness, particularly high yield strength which is about twice that of austenitic stainless steel, high thermal fatigue resistance, pitting corrosion resistance, crevice corrosion resistance, intercrystalline corrosion resistance and high weldability.

The invention discloses a rare earth permanent magnet produced by using abundant rare earth La and a preparation method of the rare earth permanent magnet. The method is a novel craft concept based on grain boundary reconstruction by atomic percentage, the main alloying component is (Nd1-x-yLaxREy) uFe100-u-v-wMvBw, the grain boundary auxiliary alloying component is R100-zM'z, the design of main alloying component and the craft of powder process aim at promoting phasing and stability of La2Fe14B, high potential elements, higher HA rare earth elements and nanometer powder are added in the compound design of main alloying component so as improve intrinsic corrosion resistance and comprehensive magnetic performance, wherein motive power of intergranular corrosion is reduced by the high potential elements, a hard magnetizing shell layer encircling the main phase boundary is formed by the higher HA rare earth elements in following sintering and technology of heating processing, and a grain boundary phase is modified by the nanometer powder. The rare earth permanent magnet produced by using the abundant rare earth La is capable of reducing cost effectively, and higher comprehensive magnetic performance and corrosion resistance performance of the magnet are guaranteed so as to satisfy market requirements.

A weldable aluminum alloy wrought product having high strength and improved resistance to intergranular corrosion, the alloy consisting essentially of, in weight percent: Si 0.2-1.3, Mg 0.4-1.5, Cu 0.1-1.1, Mn up to 0.7, Fe 0.02-0.3, Zn up to 0.9, Cr up to 0.25, Ti 0.06-0.19, Zr up to 0.2, Ag up to 0.5, and wherein 0.1<Ti+Cr<0.35, other elements and unavoidable impurities each <0.05, total <0.20, and the balance aluminum.

A process for enhancing chemical stability and corrosion resistance is described for perforated current collectors made by continuous production processes for use in electrochemical cells, including storage batteries such as lead-acid batteries. The process relies on utilizing a strip processing method, selected from the group of reciprocating expansion, rotary expansion and punching, to perforate the solid metal strip to form a grid or mesh, as a deformation treatment. The perforation-deformation treatment is followed in rapid succession by a heat-treatment to obtain a recrystallized microstructure in the current collector and optionally by quenching to rapidly reduce the temperature to below approximately 80° C. The process yields an improved microstructure consisting of a high frequency of special low Sigma CSL grain boundaries (>50%), exhibiting significantly improved resistance to intergranular corrosion and cracking. Perforated current collectors produced with this process from a solid lead-alloy strip exhibit superior growth and corrosion properties when employed as positive grids in a lead-acid battery.

The invention belongs to the technical field of an aluminum alloy thermomechanical treatment, which is particularly suitable for a 6000-series aluminum alloy. The invention provides a thermomechanical treatment method of a 6000-series aluminum alloy, aiming at the defect that in the prior art, the peak value aging state (T6) of the 6000-series aluminum alloy is high in strength and the intercrystalline corrosion is severe, so that not only the intensity of the 6000-series aluminum alloy can be improved greatly, but also the intercrystalline corrosion sensitivity is eliminated. The technical scheme provided by the invention particularly comprises the following step of: treating the 6000-series aluminum alloy sequentially in the following steps of: (1) solution treatment; (2) quenching; (3) pre-aging; (4) cold rolling and deforming; and (5) re-aging.

The invention discloses a method for improving the corrosion resistance of a sintered neodymium iron boron magnet, and relates to a permanent magnet material surface modification technology. The method mainly comprises the following steps: 1, carrying out sanding, polishing, cleaning and drying pretreatment of a sintered neodymium iron boron magnet surface for processing; 2, clamping the above obtained pretreated sintered neodymium iron boron magnet on a workbench; 3, carrying out laser irradiation of the sintered neodymium iron boron magnet surface for processing under the protection of vacuum or a gas until a grain boundary phase melts to form a micro melting pool; 4, sending metal or compound nano-powder into the grain boundary micro melting pool through a powder sending device for the micro-alloying of the nano-powder and the grain boundary phase; and 5, cleaning up unalloyed nano-powder to obtain a sintered neodymium iron boron magnet with a selectively alloying modified surface grain boundary. The method can effectively change the component and structure of the magnet surface grain boundary phase, can improve the physical and chemical properties of the grain boundary phase, can inhibit the intercrystalline corrosion of the surface of the magnet, and can substantially improve the corrosion resistance of the magnet. The method has the advantages of simple process, easy operation, and suitableness for the large-scale batch production.

A solenoid-type fuel injector assembly having at least one component formed of stabilized, solenoid-quality ferritic stainless steel. In a preferred embodiment, an austenitic fuel tube is laser-welded to an injector body and to a solenoid pole piece formed of the subject material. The stabilized, solenoid-quality ferritic stainless steel, preferably a free-machining grade thereof, comprises from about 10% to about 35% chromium, and at least one stabilizing element selected from the group consisting of titanium and columbium. Components thus formed are weldable, exhibit soft magnetic properties sufficiently strong for carrying a magnetic flux in a solenoid pole piece, have desired structural and mechanical properties, and reduce the susceptibility of a solenoid-type fuel injector to metallurgical sensitization and intergranular corrosive attack at weld sites.

The invention relates to a medical high-nitrogen nickel-free austenitic stainless steel material and a production method thereof. The material is a single-phase austenite structure and comprises the following components by weight percent: 15-18% of Cr, 10-16% of Mn, 1.5-2.5% of Mo, 0.4-0.7% of N, 0.02-0.08% of RE, less than or equal to 0.06% of unavoidable impurities and the balance of Fe. The material is free of toxic nickel, has good cytotoxicity and pyrogenic testing performances, excellent mechanical performance, higher abrasion resistance and good corrosion resistance, especially spot corrosion resistance and intergranular corrosion resistance.

The invention relates to a thermal treatment method which can improve the inter-crystalline corrosion resistance of 6000 series Al-Mg-Si-(Cu) aluminum alloy and does not reduce the tensile property of the alloy at the same time, and belongs to the technical field of thermal treatment of aluminum alloy. The method comprises the following steps: firstly, carrying out solid solution treatment for the 6000 series aluminum alloy at the temperature range of between 520 and 580 DEG C, preserving the heat for 15 to 240 minutes, quenching the aluminum alloy, and then carrying out primary ageing for 15 to 480 minutes at the temperature of between 180 and 240 DEG C; and carrying out secondary ageing for 24 to 2,400 hours at the temperature of between 130 and 170 DEG C, and finally ageing the aluminum alloy for 2 to 10 hours at the temperature of between 180 and 240 DEG C. Compared with the ageing of the conventional T6 peak value, the tensile property of the 6000 series aluminum alloy treated by the method is not reduced, and simultaneously the inter-crystalline corrosion resistance is remarkably improved.

The invention provides a non-magnetic strengthening and toughening stainless steel and a manufacturing method thereof. The non-magnetic strengthening and toughening stainless steel comprises the following mechanical components by weight percentage: C, less than or equal to 0.12 percent; Si, less than or equal to 1.5 percent; Mn, 14.5 to 16.5 percent; S, less than or equal to 0.010 percent; P, less than or equal to 0.030 percent; Cr, 15.1 to 16.0 percent; Ni, less than or equal to 0.90 percent; Mo, less than or equal to 0.70 percent; Nb, less than or equal to 0.35 percent; N, 0.25 to 0.50 percent; the rest, Fe and inevitable impurity elements. The non-magnetic strengthening and toughening stainless steel of the invention is made of the steels by the smelting process of electric furnace and refining as well as large deformation forging process at ultra low temperature. The non-magnetic strengthening and toughening stainless steel has the advantages of low cost material, simple production process, stable non-magnetism and processing hardening coefficient, stronger anti-corrosion performance and above 90 percent of qualified rate of intercrystalline corrosion resistance so as to meet the operating requirements of the steel used for a petroleum non-magnetic drill collar.

The invention discloses an intelligent response self-repairing anticorrosive coating material and a preparation method. The coating material comprises zinc oxide microcapsules and a coating matrix; each zinc oxide microcapsule comprises a capsule core and a capsule core carrier, the capsule core is a corrosion inhibitor, and the capsule core carrier is porous zinc oxide; and the outer surface of the capsule core carrier is coated with a ZIF-8 membrane. The porous inorganic material ZnO ensures the activity of the corrosion inhibitor, and the ZIF-8 membrane formed on the surface of the ZnO cannot only improve the bonding performance, but also serve as a hole sealing material to prevent premature release of the corrosion inhibitor. The invention successfully constructs the anticorrosive coating material with double effects of pH response and self-repairing. When the coating cracks, the microcapsules rupture and release the corrosion inhibitor, thereby realizing a self-repairing function; when no obvious damage is caused to the coating, and internal corrosion has already occurred, the microcapsules can be degraded and automatically release the corrosion inhibitor according to the change of pH value around a corrosion site, thereby realizing the self-repairing function.

The 904L stainless steel welding process includes two steps, including manual tungsten pole argon arc welding and acid pickling and deactivating the weld seam surface. After being treated, the joints are welded with the welding wire of 904L and the weld seam is cooled with cold water, with the welding temperature being controlled below 80 deg.c, the welding speed being 45-50 cm/min, the weld seam depth/width ratio being kept in 1.5-2, and the welded workpiece having thickness not greater than 12 mm. The weld seam is then pickled and deactivated. The present invention has the advantages of low temperature welding, no molecule conversion inside 904L stainless steel, no generation of welding faults, less integrated deformation of the welded workpiece and long service life of the welded workpiece.

The invention discloses a high-strength zinc alloy that can be drawn into thin wires at high speed, which contains 0.1%-5% copper, 0.01%-0.8% titanium or/and 0.05%-2% nickel by weight. The balance is zinc and other unavoidable impurities, and the content of impurities in the whole alloy is not more than 0.05% by weight. The product of the present invention has high strength, which can reach or even exceed the index of T2 and T3 soft (M) pure copper wires; it has good cold plastic processing performance, such as drawing wires with thinner wire diameters by high-speed drawing process , the thinnest wire diameter can reach φ0.1mm, the processing technology is simple, and it can realize industrial continuous production; it has a high working temperature; it has good corrosion resistance, small intergranular corrosion tendency, and high dimensional stability. Therefore, the present invention can replace the fine-diameter copper alloy wires used in domestic metal elastic plastic tiles, braided wires for coaxial cable shielding, and spring wires.

High-Cr ferrite stainless steel and a manufacturing method thereof belong to the technical field of stainless steel. The stainless steel comprises the following components by weight: 26.5<=Cr<=28.0, 3.4<=Mo<=3.9, 1.5<=Ni<=2.0, C<=0.032, N<=0.028, 0.4<=Nb<=0.5, Ti<=0.2, Mn<=0.2, Si<=0.23, S<=0.0039, P<=0.0083, and the balance of Fe, and meets Cr (wt%)+3.3*Mo (wt%)>=38.826. The manufacturing methodcomprises the following steps of: melting, continuous casting or mold casting, thermal grinding, hot rolling and coiling, continuous annealing treatment, oxide scale removal, cold rolling and annealing treatment, pickling and temper rolling, and welding. The advantage is that the high-Cr ferrite stainless steel has good room temperature toughness, pitting resistance, crevice corrosion resistance,stress corrosion resistance, and intergranular corrosion resistance.

The invention discloses a scandium, zirconium and strontium compound microalloyed 6013 type aluminium alloy. The invention is characterized in that the aluminium alloy is mainly composed of aluminium (Al), magnesium (Mg), silicon (Si), copper (Cu), manganese (Mn), zinc (Zn), ferrum (Fe), zirconium (Zr), strontium (Sr) and scandium (Sc); the other elements except aluminium account for 1.05-1.29%, 0.9-1.18%, 0.762-1.053%, 0.453-0.662%, 0.0902-0.117%, 0.108-0.130%, 0.0116-0.0379% and 0.045-0.078% by mass percent respectively, the balance aluminium and less impurity elements. The preparation process of the alloy includes: pure Al is melted, Al-Cu intermediate alloy, Al-Si intermediate alloy, Al-Mn intermediate alloy, Al-Zr intermediate alloy, Al-Sr intermediate alloy, Al-Sc intermediate alloy, pure Zn, pure Mg are sequentially added, refining, standing and heat preservation are carried out, then casting into ingot is carried out, and then annealing, forging and solution treatment are carried out, thus obtaining the alloy. The invention has intergranular corrosion resistance no lower than level four and stripping corrosion resistance reaching level PA, can be widely applied to the fields of modern aviation and weaponry and has wide application prospect.

The invention provides nickel-base alloy for nuclear power equipment and a manufacturing method for a nickel-base-alloy hot rolled plate. The nickel-base alloy comprises C, Cr, Fe, Mg, Ce and the balance Ni and unavoidable impurities, wherein the content of the Ni is higher than or equal to 58%. The preparing method for the hot rolled plate includes the steps of nickel-base alloy manufacturing, plate hot rolling forming and plate heat treatment. Compared with the prior art, the nickel-base alloy for the nuclear power equipment and the manufacturing method for the nickel-base-alloy hot rolled plate have the advantages that compared with the performance of an ASME SB-168UNS N06690 alloy plate, the performance of the hot rolled plate manufactured with the nickel-base alloy and the method is remarkably improved, the tensile strength of the indoor temperature can be increased by 10% about, the plasticity (extending rate) is not reduced, the excellent 350-DEG C tensile performance meeting the using requirement is achieved, the intercrystalline corrosion rate is reduced by 30% about, the corrosion resistance is better, and the nickel-base alloy is more suitable for nuclear-power criticalequipment.

An in-situ load corrosion simulation loop system of a high-temperature and high-pressure gas-liquid two-phase H2S/CO2 environment comprises a control cabinet, a high-temperature high-pressure kettle, a turbofan, a gas flowmeter, a turbine pump, a liquid flowmeter, a high-pressure-resistant flexible tube, a pressure-resistant sight glass, a temperature sensor, a test section and a hoisting device. The in-situ load corrosion simulation loop system is a corrosion loop test device which can accurately simulate the flowing regimes of dynamically changing gas-liquid two-phase flow of an oilfield site and the real stress and the dip angle of a pipe. The in-situ load corrosion simulation loop system can be used for studying the influence law and mechanism of load, dip angle and flow pattern of multiphase flow on internal corrosion of pipelines, meanwhile, can be used for evaluation and optimization study on internal pipeline sulfate reducting bacteria corrosion, internal pipeline sand-carrying scouring, a corrosion inhibitor, a bactericide and an anti-sludging agent.

The invention discloses a two-phase stainless steel electrode, which comprises a core wire and a coating, wherein the coating is coated on the outer wall of the core wire and accounts for 0.4 to 0.5 percent of the total weight of the electrode. The core wire comprises the following components in percentage by weight: 0.005 to 0.030 percent of C, 0.01 to 0.20 percent of Si, 1.50 to 2.50 percent ofMn, 0 to 0.025 percent of P, 19.0 to 22.0 percent of Cr, 9.0 to 11.0 percent of Ni, 2.5 to 3.5 percent of Mo and the balance of Fe. The coating comprises the following components in percentage by weight: 8 to 20 percent of calcium carbonate, 2 to 15 percent of barium carbonate, 5 to 15 percent of calcium fluoride, 6 to 17 percent of strontium fluoride, 4 to 16 percent of barium fluoride, 9 to 18 percent of cryolite, 4 to 10 percent of rutile, 1 to 5 percent of titanium white, 2 to 8 percent of silicon dioxide, 3 to 9 percent of chromium powder, 1 to 1.5 percent of molybdenum powder, 0.1 to 4 percent of magnesium powder and 5 to 13 percent of iron powder. After the coating components are uniformly mixed, an adhesion agent is added into the mixture. The two-phase stainless steel electrode has high strength, high tenacity and intercrystalline corrosion resistance; and during welding, an electric arc is stable, splashing phenomena is reduced, a welding seam is well molded, slag is easy toremove, and the electrode has high operability.